From 1b757dbf520b3383062584562109e4254171f005 Mon Sep 17 00:00:00 2001
From: jiriks74 <jiri@stefka.eu>
Date: Sun, 15 Dec 2024 19:23:00 +0100
Subject: [PATCH] feat: Handle API URLs for Forgejo, Gitea, GitLab and GitHub

---
 src/create-pull-request.ts |  6 ++++--
 src/github-helper.ts       | 41 ++++++++++++++++++++++++++++++++------
 2 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/src/create-pull-request.ts b/src/create-pull-request.ts
index 9076b7d..a8971a7 100644
--- a/src/create-pull-request.ts
+++ b/src/create-pull-request.ts
@@ -51,8 +51,10 @@ export async function createPullRequest(inputs: Inputs): Promise<void> {
     core.startGroup('Determining the base and head repositories')
     const baseRemote = gitConfigHelper.getGitRemote()
     // Init the GitHub clients
-    const ghBranch = new GitHubHelper(baseRemote.hostname, inputs.branchToken)
-    const ghPull = new GitHubHelper(baseRemote.hostname, inputs.token)
+    const apiUrl = await GitHubHelper.determineApiUrl(baseRemote.hostname);
+    core.info(`Using API base URL: ${apiUrl}`);
+    const ghBranch = new GitHubHelper(apiUrl, inputs.branchToken)
+    const ghPull = new GitHubHelper(apiUrl, inputs.token)
     // Determine the head repository; the target for the pull request branch
     const branchRemoteName = inputs.pushToFork ? 'fork' : 'origin'
     const branchRepository = inputs.pushToFork
diff --git a/src/github-helper.ts b/src/github-helper.ts
index 82a9296..15efc16 100644
--- a/src/github-helper.ts
+++ b/src/github-helper.ts
@@ -41,20 +41,49 @@ type TreeObject = {
 export class GitHubHelper {
   private octokit: InstanceType<typeof Octokit>
 
-  constructor(githubServerHostname: string, token: string) {
+  constructor(apiUrl: string, token: string) {
     const options: OctokitOptions = {}
     if (token) {
       options.auth = `${token}`
     }
-    if (githubServerHostname !== 'github.com') {
-      options.baseUrl = `https://${githubServerHostname}/api/v3`
-    } else {
-      options.baseUrl = 'https://api.github.com'
-    }
+    options.baseUrl = apiUrl;
     options.throttle = throttleOptions
     this.octokit = new Octokit(options)
   }
 
+  static async determineApiUrl(hostname: string): Promise<string> {
+    if (hostname === 'github.com') {
+      return "https://api.github.com";
+    }
+
+    const baseUrl = `https://${hostname}`;
+    const possiblePaths = ['/api/v4/version', '/api/forgejo/v1/version', '/api/v1/version'];
+
+    for (const path of possiblePaths) {
+      try {
+        const url = `${baseUrl}${path}`;
+        const response = await fetch(url, { method: 'GET', redirect: 'manual' }); // GitLab redirects
+                                                                                  // invalid API paths
+                                                                                  // to login prompt
+                                                                                  // which returns 200
+
+        const contentType = response.headers.get('Content-Type') || '';
+        if (
+          (response.ok || [401, 403].includes(response.status)) && // We might get 401, 403
+                                                                   // as we're unauthorised
+          contentType.includes('application/json')
+        ) {
+          return path.includes('/version') ? url.replace('/version', '') : url;
+        }
+
+      } catch (error) {
+          // Ignore errors and try the next path
+      }
+    }
+
+    throw new Error(`Unable to determine API base URL for hostname: ${hostname}`);
+  }
+
   private parseRepository(repository: string): Repository {
     const [owner, repo] = repository.split('/')
     return {